USTC Astronomy Colloquium Series: 2023 Fall
Dissecting the Baryon Cycle and ISM Properties with JWST NIRISS and NIRSpec Spectroscopy
王鑫  副教授
中国科学院大学
2023/12/05, 4:00pm , the 19th-floor Observatory Hall
报告人:
Xin Wang (王鑫) is currently an Associate Professor in the School of Astronomy and Space Science, University of Chinese Academy of Sciences (UCAS). Before professorship, Xin spent three years as a postdoctoral research associate at Caltech/IPAC. Before Caltech, Xin earned his Ph.D. in Astronomy & Astrophysics from UCLA in 2019. Xin has been the PI of two medium HST programs, awarded 45 orbits of deep near-infrared slitless spectroscopy and 38 orbits of ultra-deep near-ultraviolet imaging in cycles 28 and 30, respectively. Xin is the co-I of several JWST medium/large programs, including the 591-hour pure-parallel PASSAGE program and the GLASS ERS program. Xin is selected by NASA as one of the participants in the inaugural JWST master class, and has hosted several JWST proposal planning workshops for the community.
摘要:
Using state-of-the-art analysis methods, we reduce the new NIRISS wide-field slitless and NIRSpec multi-object spectroscopic data. The cross calibration of the two complementary spectroscopic modes opens up new key window on unbiased investigation of star formation, feedback, and ISM properties in and beyond the cosmic noon epoch. We bring forth the first spatially resolved analysis of high-redshift galaxies with JWST grism instruments and measure the first gas-phase metallicity radial gradient with sub-kpc resolution at z≥3. Using the NIRSpec slit spectroscopy in high-resolution gratings, we compile a large sample of galaxies at z~0-9 whose [S II] λ6732/[S II]λ6718 and [O II]λ3726/[O II]λ3729 line doublets are well resolved to shed light upon their ISM electron density and ionization properties. The exquisite sensitivity and wavelength coverage of the NIRSpec spectroscopy in prism mode gives us an excellent chance to identify unique spectral features in galaxies in the epoch of reionization. We discover the highest redshift galaxy, spectroscopically confirmed at z=8.1623, with PopIII-like stellar populations. This galaxy candidate hosting the first generation stars opens up new key frontiers on galaxy evolution and stellar physics in the early Universe.